chev impala 01

hi, since the day i bought my NEW 01 impala i have heard what i assumed was the windshied making a loud crack noise. i brought it in several times but the noise is not predictable, but atleast once a day. I had them use it for the weekend and heard it. They took the windshied out and replaced it back in. Still the cracking noise was heard. When I made myself a pest to manager he infomed me that there was a fix for the dashboad noise. He will call when chev can have a fix. The problem is the noise is so loud it can cause an accident very easily. Any ideas.??